Đáp án:

 B1 

a) ( -2 - 7) * ( -3 + 5)

-9 * 2 = -18

b) ( -7) ^2 * 2^3 - ( - 20)

= 49 * 8 + 20

= 49 * 28 

= 1372

c) ( - 5 - 13) / ( - 3) 

= -18 / ( -3 )

= 6

d) ( - 4 )^3 * 5^4 - 5^3

= ( - 64) * 625 - 125

= ( - 64) * 500

= - 320000

B2

a) B( 4) ∈ { 0 ; 4 ; 8 ; 12 }

b) U( - 8) ∈ { 1 ; 2 ; 4 ; 8 ; -1 ; -2 ; -4 ; -8 }

B4

a) - 81\123 = -27\41

b) 30 * 13\  -150 * 26 = -1 / 10

c) 6 * 7 - 6 * 4/ 6 + 3

 = 6 - 2 / 6 + 3

= 4 / 9

B5

a) 1/5 vs 4/20

4/ 20 = 1/5

Vi 1=1 nen 1/5 = 1/5

⇒ 1/5 = 4/20

b) 12/39 vs 16/45

12/39 = 180/585

16/45 = 208/585

Vi 180<208 nen 180/585 < 208/585

⇒ 12/39 < 16/45

c) 64/9 vs 57/8

64/9 = 512/72

57/8 = 513/72

Vi 512 < 513 nen 512/72 < 513/72

⇒ 64/9 < 57/8

d) -2/15 vs -24/72

-24/72 = -1/ 3 = -5/15

Vi -2 > -5 nen -2/15 > -5/15

⇒ -2/15 > -24/72

B5 

a) 125% = 125/100 = 5/4

 55% = 55/100 = 11/20

-0,125 =  _ 1/8

4 1/3 = 13/3

-7 1/5 = _ 36/5

b) 0,25 = 25/100 = 25%

12,9 = 12 9/10 = 129/10 = 1290/100 = 1290%

3/4 = 75/100 = 75%

2/5 = 40/100 = 40%